Radiant tube sidewall supports

ABSTRACT

A unitary cast bracket for securing radiant heating tubes to the sidewalls of indirectly heated furnaces comprising a plurality of flanges and webs arranged to support the tubes along a tangential seat.

United States Patent Roger C. Stephens Hamburg, NY. 41,443 May 28, 1970 Aug. 17, 1971 Ferro Frontiers, Inc. Bufialo, N.Y.

Inventor Appl. No. Filed Patented Assignee RADIANT TUBE SIDEWALL SUPPORTS '5 Claims, 2 Drawing Figs.

u.s. c|.....' 248/68, 122/510 Int. Cl F161 3/02 Field of Search 248/68, 62,

58; 138/108; 122/510; 263/42 TH; 126/91 A.

Primary Examiner-Chancellor E. Harris Attorney-Webb, Burden, Robinson & Webb ABSTRACTi A unitary cast bracket for securing radiant heating tubes to the sidewalls of indirectly heated furnaces comprising a plurality of flanges and webs arranged to support the tubes along a tangential seat.

SHEET 1 [IF 2 INVENTOR.

ROGER C. STEPHENS PATENTEUAUGITIQII 3.599.914

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ROGER C. STEPHENS wmwmmwmw RADIANT TUBE SIDEWALL SUPPORTS BACKGROUND Numerous indirectly heated furnaces used in industry are designed with special facilities for controlling the atmosphere in the working chamber. For example, heat-treating furnaces are used in the steel industry for such processes as annealing, normalizing, spheroidizing, hardening, tempering, carburiz ing, and stress relieving. The atmosphere within the furnace must be controlled in order to obtain desired surface conditions. For these processes, heat-treating furnaces seldom are designed for temperatures in excess of 2,000 F and generally operate'in the 800 to the I600 F. range. They are usually well insulated and built to minimizeair infiltration or loss of special atmospheres.

In heat-treating furnaces of the annealing type, means for their low heat storage capacity thus permitting rapid heating and cooling of the furnace. i

This invention pertains to controlled atmosphere heat-treating furnaces heated by radiant heating tubes. Radiant heating tubes are commonly used for indirect firing, especially where the temperature seldom exceeds the 800 to 1600 F. range. The tubes are supported in place by special brackets or supports. The tubes and the brackets generally are comprised of special alloy materials to reduce the maintenance of these parts to a minimum. Notwithstanding the use of carefully selectedalloys for the brackets as a result of the continual raising and lowering of the temperature gradient through the brackets-and other factors, after a period of time they have tended to fail by cracking and in other ways. Failure of a bracket may be disastrous as it may permit a radiant tube to fall or break open and thereby contaminate the atmosphere within the furnace. l

One very common application of the radiant tube-type heating is in the radiant tube fired covered-type furnace employed in the heat treating of coils of flat rolled products. In these furnaces the top and four sidewalls comprise a unitary removable 2 BRIEF DESCRIPTION Briefly according to this invention there is provided a unitary cast bracket for securing radiant heating tubes or the like to the sidewalls of an indirectly heated furnace, said sidewalls having an outer substantially airtight metal shell and an inner insulating lining. The bracket comprises anupright flange that is arranged to face and abut the interior surface of the insulating lining. Upper and lower extension flanges are arranged to pass through the insulating lining. They are secured at one end to the upright flange and at the other end to upper and lower fastening flanges, which in turn are fastened to the metal shell. At least a portion of the upright flange, the upper and the lower extension flanges and the upper and lower fastening flangesform a unitary C-shaped flange. A central support web is secured at its edges to the C-shaped flange.

Spaced upper and lower tube support flanges are secured to and extend away from the upright flange toward the interior of the furnace. The tube support flanges are arranged to provide a tangential seat for the radial heating tubes. Upper and lower restraining webs are shaped to restrain the movement of the radiant tubes toward and away from the insulating or metal lining while accommodating thermal expansion of the tubes and bracket.

According to a preferred aspect of this invention, a lower 7 outside support web is secured at its edges to the upright,

cover, which can be raised away from the base upon which the I coil products are positioned for treatment. Radiant tubes are positioned along at least two sidesof the cover and are often hung from the center of the cover roof. This inventionis directed primarily to brackets for securing a radiant heating tube to the sidewalls of furnaces and especially to furnaces wherein the sidewall comprises the portion of a removable cover. My copending application filed of even date entitled CENTER HUNG RADIANT TUBE SUPPORTS is directed to the center hung support brackets. .In such furnaces, the brackets must secure the radiant heating tubes to the sidewall in a manner in which they will not jar free during the transporting of the cover from one place to another.

Radiant heating tubes usually comprise a U-shaped tube wherein the diameter at the exhaust end is somewhat smaller than at the burner end. At the burner end of the tube, burning fuel-air mixtures are introduced. The exhaust products are removed at the exhaust end of the tube directed to a stack.

Prior art sidewall radiant tube support brackets have been complicated structures comprising up to as many as eight pieces. The standard bracket used throughout the steel industry for at least a quarter of a century has comprised a main casting, two restraining brackets, a tube clamp, and two locking pins. The complexity of the design has been an unfortunate drawback.

It is a feature according to this invention to provide a unitary cast bracket for supporting radiant tubes within heat-treating furnaces of the type described. It is a further feature of thisinvention to provide a tube bracket, which is more durable, more easily manufactured. less complicated to use, and a bracket which has the ability to hold radiant tubes in place along the sidewalls of an atmosphere furnace when the furnace is being transported from place to place.

lower extension and lower fastening flanges. A lower inside support web is secured at its edges to the upright flange and the ,lower support flange. According to another preferred aspect of this invention, all the webs lie in substantially the same plane, and the flanges are all substantially perpendicular to the webs.

It is further preferred that the upper and lower restraining webs have spaced substantially parallel edges such that the parallel radiant heating tubes having a fixed spatial relation therebetween maybe inserted into the restraining flanges.

According to yet another preferred embodiment of this invention, the lower inside support flange has an edge substantially parallel to the parallel edges of the upper and lower restraining flanges, whereby a plurality of brackets may be stacked or positioned, one on top of the other, and the radiant tubes inserted therein.

DETAILED DESCRIPTION Further features and other objects and advantages of this invention will become clear from the following detailed description made with reference to the drawings in which:

FIG. 1 is a pictorial view of a bracket according to a preferred embodiment of this invention.

' FIG. 2 is a broken away section view illustrating the relationship of the brackets according to this invention to the atmospheric furnace lining and to each other.

Referring now to FIG. 1, the unitary cast bracket comprises an upright flange 1, upper 2 and lower 3 extension flanges, and upper'4 andlower 5 fastening flanges. The extension flanges are secured at one end to the upright flange and at the other end to the fastening flanges. The fastening flanges are provided with openings 6 and 7 to secure them to a metal wall, for example, by bolting. A portion of the upright flange, the upper and lower extension flanges, and the fastening flanges comprise a substantially C-shaped flange. A central support web 8 is secured at its edges to the C-shaped flange. A lower outside support web 9 is secured at its edges to the upright, lower extension and fastening flanges. Spaced upper 10 and lower 11 tube support flanges are secured along one edge to the upright flange. The tube support flanges are arranged to provide a tangential seat for radiant heating tubes. By tangential seat is meant the support flange is tangent to the surface of the radiant heating tubes. In this way, the tubes during most conditions will only contact the bracket along two lines shown in FIG. I as dashed lines 15 and 16. Hence, the heat losses by conduction from the radiant heating tubes to the bracket are minimized.

A lower inside support web 12 is connected at its edges to the upright flange and the lower support flange. A lower restraining web 13 is shaped to restrain the movement of the radiant tube seated on the lower support flange toward and away from the insulating lining while accommodating thermal expansion of the tube and the bracket. The lower restraining web is secured at its edges to the upright and upper and lower support flanges. An upper restraining web 14 is secured to the upper support and upper extension flanges and is also shaped to restrain the movement of the radiant tube seated on the upper support flange toward and away from the insulating lining. The restraining webs are actually two-part webs separated to permit the support flanges to provide a tangential seat. The edge surfaces 140 and 13a of the restraining webs are curvilinear, preferably circular having a center of curvature at about the center of curvature of the radiant heating tubes when seated on the tube support flanges. The edge surfaces 13a, 13c and 14b are preferably parallel with each other. Furthermore, it is preferably that the edge surface 12a of the lower inside support web is also parallel with the edge surfaces 13a, 13c and 14b.

Throughout the specification and the claims, the webs and flanges comprising the bracket according to this invention have been described as secured to each other. It should, of course, be understood that the webs and flanges are not separately formed and joined, but are cast as one unitary member.

Referring now to FIG. 2, it is a section view through a wall of an atmospheric heat-treating furnace partially broken away to expose the relationship of a plurality of brackets according to this invention. The wall comprises an outer metal shell of 21, which is substantially airtight for containing the desired furnace atmosphere and an inner insulating flrebrick or monolithic lining 22. The flrebrick lining is only partially shown in order to expose the other pertinent features of this invention. A plurality of brackets are shown positioned against the wall and stacked one on top of the other. As can be seen, the upright flange l faces and abuts the insulating flrebrick lining. The upper and lower extension flanges 2 and 3 extend through the insulating lining, terminating in upper and lower fastening flanges 4 and 5. The flanges are secured to the outer metal shell of the furnace wall by suitable fasteners 24. The substantially parallel edge surfaces 120, [3a, 13c and 14b of the restraining webs are shown in H0. 2, and the manner in which the U-shaped radiant heating tubes 25 may be inserted in the webs is also shown by the dashed lines having arrows at each end.

It should, of course, be clear to one skilled in the art that the edge surfaces of the restraining webs 12a, 13a, 13c and 14b, which have been referred to as substantially parallel, may also be nonparallel, so long as the restraining webs of the brackets stacked one on top of the other provide spaced parallel pathways for the insertion of the U-shaped combustion tubes into the bracket. The pathways should preferably form an angle of between 30 and 60 with the plane of the upright flange 1.

Having thus defined my invention in detail with the particularity required by Patent Laws, what I claim and what is desired to have protected by Letters Patent are set forth in the following:

1. A unitary cast bracket for securing radiant heating tubes to the sidewalls of an indirectly heated furnace, said sidewalls having an outer substantially airtight metal shell and an inner insulating lining, said bracket comprising:

an upright flange arranged to face and abut the interior surface of the insulating lining;

spaced upper and lower extension flanges arranged to pass through the insulating lining, said extension flanges secured to the upright flange;

spaced upper and lower fastening flanges arranged to abut and be fastened to the metal shell, said fastening flanges secured to the upper and lower extension flanges respectively, such that at least a portion of the u right flange, the upper and lower extension flanges and t e upper and lower fastening flanges form a unitary C-shaped flange;

a central support web secured at its edges to the C-shaped flange, a lower outside support web secured at its edges to the upright, lower extension and lower fastening flanges;

spaced upper and lower tube support flanges secured to and extending away from the upright flange, the said tube support flanges arranged to provide a tangential seat for the radiant tubes;

a lower inside support web secured at its edges to the upright flange and the lower support flange;

upper and lower restraining webs shaped to restrain the movement of radiant tubes toward and away from the refractory lining while accommodating thermal expansion of the tubes and bracket, said upper restraining web secured at its edges to the upper support flange and the upper extension flange, said lower restraining web secured at its edges to the upright and upper and lower support flanges.

2. The bracket according to claim 1 wherein the webs all lie substantially in the same plane and the flanges are all substantially perpendicular to said webs.

3. The bracket according to claim 2 wherein the upper and lower restraining webs and lower inside support web have spaced substantially parallel edge surfaces, such that U- shaped radiant heating tubes may be inserted into the restraining flanges.

4. The bracket according to claim 2 wherein the edges of the restraining webs and the lower inside support web are shaped to provide parallel pathways for the insertion of U- shaped radiant heating tubes.

5. The bracket according to claim 4 wherein the parallel pathways form an angle between 30 and 60 with the upright flange. 

1. A unitary cast bracket for securing radiant heating tubes to the sidewalls of an indirectly heated furnace, said sidewalls having an outer substantially airtight metal shell and an inner insulating lining, said bracket comprising: an upright flange arranged to face and abut the interior surface of the insulating lining; spaced upper and lower extension flanges arranged to pass through the insulating lining, said extension flanges secured to the upright flange; spaced upper and lower fastening flanges arranged to abut and be fastened to the metal shell, said fastening flanges secured to the upper and lower extension flanges respectively, such that at least a portion of the upright flange, the upper and lower extension flanges and the upper and lower fastening flanges form a unitary C-shaped flange; a central support web secured at its edges to the C-shaped flange, a lower outside support web secured at its edges to the upright, lower extension and lower fastening flanges; spaced upper and lower tube support flanges secured to and extending away from the upright flange, the said tube support flanges arranged to provide a tangential seat for the radiant tubes; a lower inside support web secured at its edges to the upright flange and the lower support flange; upper and lower restraining webs shaped to restrain the movement of radiant tubes toward and away from the refractory lining while accommodating thermal expansion of the tubes and bracket, said upper restraining web secured at its edges to the upper support flange and the upper extension flange, said lower restraining web secured at its edges to the upright and upper and lower support flanges.
 2. The bracket according to claim 1 wherein the webs all lie substantially in the same plane and the flanges are all substantially perpendicular to said webs.
 3. The bracket according to claim 2 wherein the upper and lower restraining webs and lower inside support web have spaced substantially parallel edge surfaces, such that U-shaped radiant heating tubes may be inserted into the restraining flanges.
 4. The bracket according to claim 2 wherein the edges of the restraining webs and the lower inside support web are shaped to provide parallel pathways for the insertion of U-shaped radiant heating tubes.
 5. The bracket according to claim 4 wherein the parallel pathways form an angle between 30* and 60* with the upright flange. 